• Title/Summary/Keyword: Sodium Borohydride($NaBH_4$)

Search Result 74, Processing Time 0.028 seconds

Study on the Stability of NaBH4 Solution during Storage Process (NaBH4수용액 저장과정 중 안정성에 관한 연구)

  • Sim, Woojong;Jo, Jaeyoung;Choi, Daeki;Nam, Sukwoo;Park, Kwonpil
    • Korean Chemical Engineering Research
    • /
    • v.48 no.3
    • /
    • pp.322-326
    • /
    • 2010
  • Stability of sodium borohydride solution during storage was studied. In order to enhance the $NaBH_4$ stability, NaOH and KOH were added to the $NaBH_4$ solution. The effect of concentration of the borohydride and alkaline solution, temperature and materials of storage vessels on the rate of borohydride hydrolysis was investigated. The rate of hydrogen evolution decreased as the concentration of alkaline increased due to increase of $NaBH_4$ stability in the solution. The stability of $NaBH_4$ solution decreased when the borohydride concentration raised from 10 to 15 wt% and then increased when the $NaBH_4$ concentration increased above 15 wt% due to increase in the pH of the concentrated solution. The activity coefficient of hydrolysis of $NaBH_4$ solution(NaOH 3.0 wt%, $NaBH_4$ 25 wt%) was 115.1 kJ/mol and this value was 1.5~4.0 times higher than that of hydrolysis of $NaBH_4$ solution with catalyst. The borohydride solutions in glass and stainless-steel vessel were more stable than the solution in plastic(PE) vessel.

The Hydrogen Generation System Using Sodium Borohydride for Small Fuel Cells ($NaBH_4$를 이용한 소형연료전지용 수소저장시스템 개발)

  • 강순기;한기철;조준배;박태희;유용호
    • 한국전기화학회:학술대회논문집
    • /
    • 2004.06a
    • /
    • pp.129-134
    • /
    • 2004
  • 문헌 연구를 통해 최적의 수소저장물질의서 수소저장 효율, 물질의 안정성 및 경제성이 우수한 나트륨붕소수소화물($NaBH_4$, sodium borohydride)을 선정하여, 소형연료전지용 수소저장시스템에 대한 다양한 특성을 조사하였다. $NaBH_4$의 기초 물성 조사를 위해 수소 발생 능력, 용해도, 수소 비발생 등의 실험을 수행하였으며 다양한 촉매의 특성비교는 물론 수소저장시스템의 설계시 핵심적으로 고려할 수 있는 Key factor의 특성을 파악하였다.

  • PDF

Development of an Catalyst for Hydrolysis of Aqueous Sodium Borohydride Solution ($NaBH_4$ 수용액 분해 수소 발생용 최적 촉매 개발)

  • Yang Tae-Hyun;Krishnan Palanichamy;Lee Won-Yong;Kim Chang-Soo
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2005.06a
    • /
    • pp.296-298
    • /
    • 2005
  • Hydrogen generation by the hydrolysis of aqueous sodium borohydride $(NaBH_4)$ solutions was studied using IRA-400 anion resin dispersed Pt. Ru catalysts and Lithium Cobalt oxide $(LiCoO_2)$ supported Pt, Ru and PtRu catalysts. The performance of the $LiCoO_2$ supported catalysts is better than the ion exchange resin dispersed catalysts. There is a marked concentration dependence on the performance of the $LiCoO_2$ supported catalysts and the hydrogen generation rate goes down if the borohydride concentration is increased beyond $10\%$. The efficiency of PtRu- $LiCoO_2$ is almost double that of either Ru-$LiCoO_2$ or Pt-$LiCoO_2$ for $NaBH_4$ concentrations up to $10\%$.

  • PDF

A Study on Anode Fuel Composition of Direct Borohydride/Hydrogen Peroxide Fuel Cell (직접 수소화붕소나트륨/과산화수소 연료전지의 산화극 연료 조성에 관한 연구)

  • LEE, TAE HOON;YU, SU SANG;OH, TAEK HYUN
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.32 no.6
    • /
    • pp.514-523
    • /
    • 2021
  • This study investigated the effect of anode fuel composition on the performance of direct borohydride/hydrogen peroxide fuel cells (DBHPFCs). The effect of sodium borohydride (NaBH4) and sodium hydroxide (NaOH) concentrations on fuel cell performance was determined through fuel cell tests. Fuel cell performance increased with an increase in the NaBH4 concentration, whereas it decreased with an increase in the NaOH concentration. The anode fuel composition was selected as 10 wt% NaBH4+10 wt% NaOH+80 wt% H2O based on the fuel viscosity, electrochemical reaction rate, and decomposition reaction rate. DBHPFCs were also tested to analyze the effect of operating temperature and operation time on fuel cell performance. The present results can be used as a reference basis to determine operating conditions of DBHPFCs.

Catalytic Hydrolysis of Sodium Borohydride on LiCoO3 - Supported Pt, Ru Catalysts (LiCoO3에 담지된 Pt, Ru 촉매에 의한 NaBH4 가수분해반응)

  • Ahn, Jong-Gwan;Choi, Seung-Hoon;Lee, Su-Chol
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.13 no.7
    • /
    • pp.3261-3266
    • /
    • 2012
  • Sodium borohydride($NaBH_4$) known as the material of hydrogen generation and storage can produce the hydrogen via catalytic hydrolysis. This protide chemical could be used in the hydrogen supply system for residential and mobile fuel cells, and thus many researches and developments regarding to these chemicals and decomposition reactions have been implemented. We experimented the hydrolysis of $NaBH_4$ alkaline solution by metal oxide-supported PGM(platinum group metal) catalysts and measured the generation rate of hydrogen which is product of decomposition reaction. We compared oxides as catalyst supports, and the precious metals, Pt and Ru for the catalysts and studied the effects of amounts of catalyst added and $NaBH_4$ concentrations on the hydrogen generation rates and patterns.

Study on the Hydrogen Yield of $NaBH_4$ Hydrolysis Reaction ($NaBH_4$ 가수분해반응에서 수소 수율에 관한 연구)

  • Hwang, Byungchan;Jo, Jaeyoung;Sin, Sukjae;Choi, Daeki;Nam, Sukwoo;Park, Kwonpil
    • Korean Chemical Engineering Research
    • /
    • v.49 no.5
    • /
    • pp.516-520
    • /
    • 2011
  • Sodium borohydride, $NaBH_4$, shows a number of advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFCs). The hydrogen yield of sodium borohydride hydrolysis reaction was studied. The effect of temperature, $NaBH_4$ concentration, NaOH concentration and catalyst type on the hydrogen yield from $NaBH_4$ hydrolysis reaction were measured. The catalysts of Co-P/Cu, Co-B/Cu and Co-P-B/Cu were used in this study and there was no different effect of these catalysts on the hydrogen yield from $NaBH_4$. Under the temperature of $60^{\circ}C$, the hydrogen yield decreased as $NaBH_4$ concentration increased due to formation of gel with by-products and reactants. The gel formed during $NaBH_4$ hydrolysis reaction diminished the hydrogen evolution rate and total volume of hydrogen. Addition of NaOH stabilizer enhanced the formation of gel and then decreased the hydrogen yield.

Planar, Air-breathing PEMFC Systems Using Sodium Borohydride ($NaBH_4$를 이용만 공기호흡형 수소연료전지에 대한 연구)

  • Kim, Jin-Ho;Hwang, Kwang-Taek
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.20 no.4
    • /
    • pp.300-308
    • /
    • 2009
  • In a pursuit of the development of alternative mobile power sources with a high energy density, a planar and air-breathing PEMFCs with a new type of hydrogen cartridge which uses onsite $H_2$ generated from sodium borohydride ($NaBH_4$) hydrolysis have been investigated for use in advanced power systems. Two types of $H_2$ generation through $NaBH_4$ hydrolysis are available: (1) using organic acids such as sulphuric acid, malic acid, and sodium hydrogen carbonate in aqueous solution with solid $NaBH_4$ and (2) using solid selected catalysts such as Pt, Ru, CoB into the stabilized alkaline $NaBH_4$ solution. It might therefore be relevant at this stage to evaluate the relative competitiveness of the two methods mentioned above. The effects of flow rate of stabilized $NaBH_4$ solution, MEA (Membrane Electrode Assembly) improvement, and type and flow control of the catalytic acidic solution have been studied and the cell performances of the planar, air-breathing PEMFCs using $NaBH_4$ has been measured from aspects of power density, fuel efficiency, energy density, and fast response of cell. In our experiments, planar, air-breathing PEMFCs using $NaBH_4$ achieved to maximum power density of 128mW/$cm^2$ at 0.7V and energy efficiency of 46% and has many advantages such as low operating temperature, sustained operation at a high power density, compactness, the potential for low cost and volume, long stack life, fast star-up and suitability for discontinuous operation.

Durability of Co-P-B/Cu Catalyst for NaBH4 Hydrolysis Reaction (NaBH4 가수분해용 Co-P-B/Cu 촉매의 내구성)

  • Hwang, Byungchan;Jo, Ara;Sin, Sukjae;Choi, Daeki;Nam, Sukwoo;Park, Kwonpil
    • Korean Chemical Engineering Research
    • /
    • v.50 no.4
    • /
    • pp.627-631
    • /
    • 2012
  • Sodium borohydride, $NaBH_4$, shows a number of advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFCs). The durability of Co-P-B/Cu catalyst for sodium borohydride hydrolysis reaction was studied. The effect of reaction temperature, $NaBH_4$ concentration, NaOH concentration and calcination temperature of catalyst on the durability of Co-P-B/Cu catalyst were measured. The gel formed during hydrolysis reaction affected the durability of catalyst (loss of catalyst). Formation of gel increased the loss of the catalyst. When $NaBH_4$ concentration was high and reaction temperature was higher than $60^{\circ}C$, loss of catalyst was low because gel was not formed. But under the temperature of $40^{\circ}C$, loss of catalyst increased due to gel formation When $NaBH_4$ concentration was 40 weight % and the reaction temperature was $40^{\circ}C$, the loss of catalyst increased as the NaOH concentration increased. As the calcination temperature of catalyst decreased, the loss of catalyst decreased and the activity of catalyst decreased. Calcination of the catalyst at high temperature enhanced the durability of catalyst but diminished the activity of catalyst.

Development of High Performance Co Catalysts for Hydrogen Generation from Sodium Borohydride Solution (Sodium Borohydride 용액의 수소 발생을 위한 고성능 Co 촉매 개발)

  • 조근우;엄광섭;권혁상
    • 한국전기화학회:학술대회논문집
    • /
    • 2005.07a
    • /
    • pp.341-346
    • /
    • 2005
  • 펄스 도금 조건이 Co 도금층의 미세 구조 및 알칼리 $NaBH_4$ 용액의 수소발생특성에 미치는 영향을 조사하였다. 펄스 주기 및 최대전류밀도가 증가함에 따라 polyhedral 형상의 Co 결정립이 triangular형상으로 변화하였으며, 점차 결정립이 조대화 되어, 촉매 표면적이 감소하였다. 결국 알칼리 $NaBH_4$ 용액 내에서 가수분해반응에 참여하는 촉매 site가 감소하여 수소발생속도가 낮아졌다. 펄스도금시간이 증가함에 따라 Co 결정립의 크기가 점차 증가하여 촉매 표면적이 감소하였고, 가수분해반응에 참여하지 못하는 CO의 양이 증가하여 수소발생속도가 크게 감소하였다. 최대전류밀도 $0.1\;A/cm^2$, 펄스 주기 2 mS에서 10 s 동안 펄스 도금 시, $25^{\circ}C\;1\;wt.\%\;NaOH\;+\;10\;wt.\%\;NaBH_4$ 용액에서 $2140\;ml/min{\cdot}g-catalyst$의 높은 수소발생속도를 가지는 것으로 나타났다.

  • PDF